A solid state image forming device, which is used for a digital camera, a build-in camera of a cellular phone, or a monitoring camera as an area sensor, converts light detected by a photodiode into charges, transfers the converted charges by a CCD (Charge Coupled Device) or a CMOS device, and outputs the resultant.
There has been known, as the solid state image forming device described above, the one having a plural rectangular photodiodes arranged and formed on a semiconductor substrate in a lattice, a color filter layer formed on each of the photodiodes, and a plurality of circular microlenses arranged on the respective color filter layers in such a manner that a part of the circumference of the respective microlenses is in contact with each other.
According to the solid state image forming device described above, since the adjacent microlenses are formed to be in contact with each other, even the light incident between the adjacent microlenses is converged onto the photodiode. Therefore, a solid state image forming device having a high sensitivity can be formed.
However, the planar shape of the microlens is circular, so that the microlens is not formed on the corner of the rectangular color filter. Accordingly, the light incident on this portion is reflected by a wiring layer formed between the semiconductor substrate and the color filter layer, and not converged onto the photodiode. Therefore, there arises a problem that it is difficult to more enhance the sensitivity.